Okay, this is my first time having to ask a question... it is a dandy!
I have a 91 Z28 Camaro with an automatic trans and a 305 TPI.
I have recently installed TWO new fuel pumps, new MAP sensor, checked the fuel pump relay, car is holding 42 lbs. of fuel pressure at idle and pressure goes up when I press the accelerator. Yesterday I had a well known mechanic to come up and he put a scan tool on the car and all sensors seemed to be in normal parameter.
The car will run good until the car goes in to close loop. As soon as the computer closes the loop in starts idling realy bad and won't take fuel. It actualy will die, sometimes it will start back and others it will take a shot of ether to get it back running. Once you get it started back it will sit and idle realy rough, but won't die.
The TPS tested okay!
I can jump over the wires going to the fuel pump relay and start the car and it doesn't change anything.
Is there anyway that the fuel pressure could be reading good, but still not getting to the injectors?
I can listen to the injectors and her all of them working.
I don't understand what the computer could be reading that is making the car run so bad.
I TRULY DO APPRECIATE ANY HELP THAT ANYONE CAN GIVE

 

I've worked on two different F-bodies with TPI that had fuel, spark, injector pulse and no codes in computer. Hooking up scanner they both had readings that were normal. I was able to borrow a reman computer from a parts store and in both cases the problems went away.

 

map or maf

 

He has a MAP car, its a '91... and he installed a new MAP sensor.

So, what does the scan tool say while the engine is running in closed loop? And how do you know its in closed loop? Also, what is the fuel pressure while the engine runs rough? I assume that there are no DTC codes.

 

Turned out to be 2 bad injectors!